MASON CITY, Ia. (AP) — A man accused of stabbing his grandparents to death in the Mason City home they shared has pleaded guilty in the case.

Codie Matz, 25, was charged with two counts of first-degree murder in the deaths of 61-year-old Kenneth Hackbart and 62-year-old Kathleen Hackbart. The couple was found stabbed to death at their home Nov. 7.

Television station KIMT reported Matz changed his plea Tuesday to guilty, saying he wants to take responsibility for the crime. He had pleaded not guilty in March.

"I stabbed Ken to death, and I stabbed Kathy to death," Matz said Tuesday in a Cerro Gordo County courtroom, the Globe Gazette reported.

Matz faces life in prison when he's sentenced July 23.

In February, a judge ruled he was competent for trial after his attorneys filed court documents saying it "appears the defendant is suffering from a mental disorder."

Mason City police conducted a welfare check Nov. 7 at a residence at 327 27th St. SW., where officers found the two bodies.

Police had requested the public's assistance in finding Matz after the discovery. An Iowa State Patrol trooper then found him near a home in Bondurant, authorities said.